Tape, Strip or Integrator: Which Chemical Indicator Goes Where on a Load
A mismatch between what a clinic thinks its indicators do and what they actually do shows up in one of two ways: a load gets released on the strength of a colour change that never tested the hard part of the pack, or a team buys four different indicator products and stops being able to explain which one is doing which job.
The indicator classes in ISO 11140-1 exist to stop exactly that confusion. They describe what each type measures, which tells you where it belongs on a load.
What does each indicator class actually measure?
| ISO 11140-1 type | What it responds to | Typical use | Where it goes |
|---|---|---|---|
| Class 1 | One or more process variables, process indicator | Indicator tape on pack closure, process labels | Outside the package |
| Class 2 | A specific test procedure | Bowie-Dick test pack for pre-vacuum air removal | Empty chamber, start of day |
| Class 3 | A single critical variable | Single-variable chemical indicator | Inside the package where specified |
| Class 4 | Two or more critical variables | Printed internal indicator on clinic pouches | Inside the package |
| Class 5 | All critical variables, integrated | Load integrator for release decisions | Most challenging position in the load |
| Class 6 | Cycle-specific emulation | Cycle-specific indicator for a defined profile | Inside the package or in the load |
Reading the table as a placement plan is the useful move. Class 1 goes on the outside because it is about identity and route. Classes 3 to 6 go inside, because the whole point is to test whether steam reached the instruments. Class 2 does not belong on a load at all - it is a chamber test.
Why does placement matter more than the product?
Because sterilization is a penetration problem, not a temperature problem. A dense tray of instruments inside a sealed pouch presents a much harder challenge than the corner of the chamber, and the outside of a package is the easiest place in the load to reach.
Place the indicator where the steam is slowest to arrive. In practice that means the centre of a wrapped tray, the middle of a stack, or alongside the densest instrument set - and for implant loads, one indicator at the known worst position in the chamber.
What should a clinic actually stock?
Most dental and medical clinics need three things and can do without a fourth:
- Indicator tape for closure and for distinguishing processed packs from unprocessed ones, at CA $14.99 for a three-roll set.
- Pouches with a printed internal Class 4 indicator, so every package carries its own internal check.
- A Class 5 integrator, CA $14.99 for 100, placed in the hardest part of each load.
- A Bowie-Dick test pack if the sterilizer is pre-vacuum and runs a daily air-removal test.
Write the placement rule into the reprocessing procedure in one sentence - process indicator outside, internal indicator inside, integrator in the hardest position, spore test on schedule - and the choice stops being a judgement call at 8 a.m. Teams that want to see the full chain before committing to a routine can start with a five-pack biological indicator trial at CA $12.99 with shipping included and run one monitored load a week while they settle the procedure.
References
- CSA Z314:23, Canadian medical device reprocessing standard (CSA Group) (checked 16 September 2026)
- Public Health Ontario - reprocessing of medical devices, infection prevention and control (checked 16 September 2026)
- RCDSO infection prevention and control guideline, standards and guidelines (checked 16 September 2026)
Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers case pricing and account setup, and the B2B wholesale collection lists the lines stocked for institutional buyers.
Related Reading
- Dental compliance hub: sterilization records, indicators and reprocessing expectations
- Is autoclave indicator tape the same as indicator test strips?
- Bowie-Dick test packs compared: 3M Comply, Crosstex and open options
- Dental sterilization essentials: pouches, indicators and monitoring consumables
- dental clinic sterilization supplies
- free Ontario sterilization compliance log
- printable autoclave sterilization log sheet (free)
Frequently Asked Questions
Can indicator tape replace an internal indicator?
No. Tape is a process indicator that tells you a package went through a cycle - useful for pack closure and for separating processed from unprocessed items, but it says nothing about conditions inside the pack. An internal indicator sits next to the instruments, where steam actually has to reach, so it is the one that reflects the challenge your load presents.
Do we need a Class 5 integrator in every pouch?
Most clinic pouches already carry a Class 4 multi-variable indicator printed inside, and a separate Class 5 integrator is added to the load rather than to every package. Practices that process implants or dense instrument sets place one integrator in the most challenging position, which is usually the centre of the tray or the middle of the rack, not the edge.
Where does the Bowie-Dick test fit in?
The Bowie-Dick test is a Type 2 specific test for pre-vacuum sterilizers. It is run on an empty chamber at the start of the day to confirm that air removal is working, and it is not a substitute for a load indicator or a spore test. A pack that passes Bowie-Dick in an empty chamber can still fail on a heavy load.
What is the difference between Class 4, 5 and 6?
Class 4 is multi-variable: it responds to more than one critical variable but does not integrate them. Class 5 is integrating - it is designed to react to all critical variables across the full cycle parameters, which is why it is often used as a load-release indicator. Class 6 is emulating: it is calibrated to the performance of a specified sterilization cycle, so it is tied more tightly to a particular cycle profile.
Last updated: September 2026. CliniEco Medical holds MDEL #35334 issued by Health Canada, and supplies clinics, long-term care homes and home-care programs across Canada.
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